<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    #d1{
      width: 100px;height: 100px;
      border: 1px solid red;
      /*单独某一个方向添加外边距*/
      margin-left: 100px;
      margin-top: 100px;
      margin-bottom: 100px;
      margin-right: 100px;
      /*上下左右设置外边距*/
      margin: 10px;
      /*上下、左右外边距*/
      margin: 50px 100px;
      /*外边距自动剧中（左右自动居中）*/
      margin: 0 auto;
      /*上右下左顺时针赋值*/
      margin: 10px 20px 30px 40px;
    }
    #d2{
      width: 100px;height: 100px;
      border: 1px solid red;
      /*上下相邻 彼此添加外边距取最大值*/
      margin-top: 50px;
        margin-right: 50px;
    }
    #s1{
        border: 1px solid red;
      margin-left: 50px;
      /*行内元素上下外边距无效*/
      margin-top: 50px;
    }
    #s2{
        border: 1px solid red;
        /*左右相邻 彼此添加外边距为两个外边距相加*/
        margin-left: 50px;
    }
    #big{
        width: 200px;
        height: 200px;
        background-color: red;
        overflow: hidden;
    }
    #big>div{
        width: 50px;height: 50px;
        background-color: green;
        margin-left: 100px;
        /*当元素的上边缘和上级元素的上边缘重叠时
        给元素添加上外边距会显示粘连异常
        给上级元素添加overflow：hidden解决*/
        margin-top: 100px;
    }
  </style>
</head>
<body>
<div id="big"><div></div></div>
<span id="s1">span1</span><span id="s2">span2</span>
<div id="d1"></div><div id="d2"></div>
</body>
</html>